package com.zuorenke.help;

import lombok.extern.slf4j.Slf4j;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.reflections.Reflections;
import org.reflections.util.ClasspathHelper;
import org.reflections.util.ConfigurationBuilder;
import org.reflections.util.FilterBuilder;

import java.io.IOException;
import java.lang.reflect.*;
import java.util.List;
import java.util.stream.Stream;
@Slf4j
public class ReflectionUtils {
	private static final String SETTER_PREFIX = "set";
	
	private static final String GETTER_PREFIX = "get";
	
	private static final String CGLIB_CLASS_SEPARATOR = "$$";
	
	public static Reflections getReflections(String packageAddress) {
		ConfigurationBuilder configurationBuilder = new ConfigurationBuilder();
		FilterBuilder filterBuilder = new FilterBuilder();
		String[] addresses = packageAddress.split(",");
		Stream.of(addresses).forEach(str -> configurationBuilder.addUrls(ClasspathHelper.forPackage(str.trim())));
		filterBuilder.includePackage(addresses);
		configurationBuilder.filterInputsBy(filterBuilder);
		return new Reflections(configurationBuilder);
	}
	
	public static Reflections getReflections(List<String> packageAddresses) {
		ConfigurationBuilder configurationBuilder = new ConfigurationBuilder();
		FilterBuilder filterBuilder = new FilterBuilder();
		packageAddresses.forEach(str -> {
			configurationBuilder.addUrls(ClasspathHelper.forPackage(str.trim()));
			filterBuilder.includePackage(str.trim());
		});
		configurationBuilder.filterInputsBy(filterBuilder);
		return new Reflections(configurationBuilder);
	}
	
	/**
	 * 调用Getter方法.
	 */
	public static Object invokeGetter(Object obj, String propertyName) {
		String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(propertyName);
		return invokeMethod(obj, getterMethodName, new Class[] {}, new Object[] {});
	}
	
	/**
	 * 调用Setter方法, 仅匹配方法名。
	 */
	public static void invokeSetter(Object obj, String propertyName, Object value) {
		String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(propertyName);
		invokeMethodByName(obj, setterMethodName, new Object[] { value });
	}
	
	/**
	 * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
	 */
	public static Object getFieldValue(final Object obj, final String fieldName) {
		Field field = getAccessibleField(obj, fieldName);
		
		if (field == null) {
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
		}
		
		Object result = null;
		try {
			result = field.get(obj);
		} catch (IllegalAccessException e) {
			log.error("不可能抛出的异常{}", e.getMessage());
		}
		return result;
	}
	
	/**
	 * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
	 */
	public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
		Field field = getAccessibleField(obj, fieldName);
		
		if (field == null) {
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
		}
		
		try {
			field.set(obj, value);
		} catch (IllegalAccessException e) {
			log.error("不可能抛出的异常:{}", e.getMessage());
		}
	}
	
	/**
	 * 直接调用对象方法, 无视private/protected修饰符.
	 * 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用.
	 * 同时匹配方法名+参数类型，
	 */
	public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes, final Object[] args) {
		Method method = getAccessibleMethod(obj, methodName, parameterTypes);
		if (method == null) {
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
		}
		
		try {
			return method.invoke(obj, args);
		} catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}
	}
	
	public static Object invokeConstructor(final Class<? extends Object> clazz, final Class<?>[] parameterTypes, final Object[] args) {
		Object result = null;
		try {
			Constructor constructor = clazz.getDeclaredConstructor(parameterTypes);
			constructor.setAccessible(true);
			result = constructor.newInstance(args);
		}catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}
		return result;
	}
	
	/**
	 * 直接调用对象方法, 无视private/protected修饰符，
	 * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
	 * 只匹配函数名，如果有多个同名函数调用第一个。
	 */
	public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
		Method method = getAccessibleMethodByName(obj, methodName);
		if (method == null) {
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
		}
		
		try {
			return method.invoke(obj, args);
		} catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}
	}
	
	/**
	 * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.
	 *
	 * 如向上转型到Object仍无法找到, 返回null.
	 */
	public static Field getAccessibleField(Class<? extends Object> clazz, final String fieldName) {
		if (null == clazz) {
			throw new IllegalArgumentException("object can't be null");
		}
		if (StringUtils.isEmpty(fieldName)) {
			throw new IllegalArgumentException("fieldName can't be blank");
		}
		for (Class<?> superClass = clazz; superClass != Object.class; superClass = superClass.getSuperclass()) {
			try {
				Field field = superClass.getDeclaredField(fieldName);
				makeAccessible(field);
				return field;
			} catch (NoSuchFieldException e) {//NOSONAR
				// Field不在当前类定义,继续向上转型
			}
		}
		return null;
	}
	
	
	public static Field getAccessibleField(final Object obj, final String fieldName) {
		if (null == obj) {
			throw new IllegalArgumentException("object can't be null");
		}
		if (StringUtils.isEmpty(fieldName)) {
			throw new IllegalArgumentException("fieldName can't be blank");
		}
		for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
			try {
				Field field = superClass.getDeclaredField(fieldName);
				makeAccessible(field);
				return field;
			} catch (NoSuchFieldException e) {//NOSONAR
				// Field不在当前类定义,继续向上转型
			}
		}
		return null;
	}
	
	/**
	 * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
	 * 如向上转型到Object仍无法找到, 返回null.
	 * 匹配函数名+参数类型。
	 *
	 * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
	 */
	public static Method getAccessibleMethod(final Object obj, final String methodName, final Class<?>... parameterTypes) {
		if (null == obj) {
			throw new IllegalArgumentException("object can't be null");
		}
		if (StringUtils.isEmpty(methodName)) {
			throw new IllegalArgumentException("methodName can't be blank");
		}
		
		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
			try {
				Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
				makeAccessible(method);
				return method;
			} catch (NoSuchMethodException e) {
				// Method不在当前类定义,继续向上转型
			}
		}
		return null;
	}
	
	/**
	 * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
	 * 如向上转型到Object仍无法找到, 返回null.
	 * 只匹配函数名。
	 *
	 * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
	 */
	public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
		if (null == obj) {
			throw new IllegalArgumentException("object can't be null");
		}
		if (StringUtils.isEmpty(methodName)) {
			throw new IllegalArgumentException("methodName can't be blank");
		}
		
		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
			Method[] methods = searchType.getDeclaredMethods();
			for (Method method : methods) {
				if (method.getName().equals(methodName)) {
					makeAccessible(method);
					return method;
				}
			}
		}
		return null;
	}
	
	/**
	 * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
	 */
	public static void makeAccessible(Method method) {
		if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) {
			method.setAccessible(true);
		}
	}
	
	/**
	 * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
	 */
	public static void makeAccessible(Field field) {
		if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier.isFinal(field.getModifiers())) && !field.isAccessible()) {
			field.setAccessible(true);
		}
	}
	
//	/**
//	 * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处
//	 * 如无法找到, 返回Object.class.
//	 * eg.
//	 * public UserDao extends HibernateDao<User>
//	 *
//	 * @param clazz The class to introspect
//	 * @return the first generic declaration, or Object.class if cannot be determined
//	 */
//	public static <T> Class<T> getClassGenricType(final Class clazz) {
//		return getClassGenricType(clazz, 0);
//	}

//	/**
//	 * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
//	 * 如无法找到, 返回Object.class.
//	 *
//	 * 如public UserDao extends HibernateDao<User,Long>
//	 *
//	 * @param clazz clazz The class to introspect
//	 * @param index the Index of the generic ddeclaration,start from 0.
//	 * @return the index generic declaration, or Object.class if cannot be determined
//	 */
//	public static Class getClassGenricType(final Class clazz, final int index) {
//
//		Type genType = clazz.getGenericSuperclass();
//
//		if (!(genType instanceof ParameterizedType)) {
//			log.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
//			return Object.class;
//		}
//
//		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
//
//		if (index >= params.length || index < 0) {
//			log.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: " + params.length);
//			return Object.class;
//		}
//		if (!(params[index] instanceof Class)) {
//			log.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
//			return Object.class;
//		}
//
//		return (Class) params[index];
//	}
	
	public static Class<?> getUserClass(Object instance) {
		if(null == instance ){
			throw new NullPointerException("Instance must not be null");
		}
		Class clazz = instance.getClass();
		if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
			Class<?> superClass = clazz.getSuperclass();
			if (superClass != null && !Object.class.equals(superClass)) {
				return superClass;
			}
		}
		return clazz;
		
	}
	
	/**
	 * 将反射时的checked exception转换为unchecked exception.
	 */
	public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
		if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException || e instanceof NoSuchMethodException) {
			return new IllegalArgumentException(e);
		} else if (e instanceof InvocationTargetException) {
			return new RuntimeException(((InvocationTargetException) e).getTargetException());
		} else if (e instanceof RuntimeException) {
			return (RuntimeException) e;
		}
		return new RuntimeException("Unexpected Checked Exception.", e);
	}
	
	/**
	 * Handle the given reflection exception. Should only be called if no
	 * checked exception is expected to be thrown by the target method.
	 * <p>Throws the underlying RuntimeException or Error in case of an
	 * InvocationTargetException with such a root cause. Throws an
	 * IllegalStateException with an appropriate message else.
	 * @param ex the reflection exception to handle
	 */
	public static void handleReflectionException(Exception ex) {
		if (ex instanceof NoSuchMethodException) {
			throw new IllegalStateException("Method not found: " + ex.getMessage());
		}
		if (ex instanceof IllegalAccessException) {
			throw new IllegalStateException("Could not access method: " + ex.getMessage());
		}
		if (ex instanceof InvocationTargetException) {
			handleInvocationTargetException((InvocationTargetException) ex);
		}
		if (ex instanceof RuntimeException) {
			throw (RuntimeException) ex;
		}
		throw new UndeclaredThrowableException(ex);
	}
	
	/**
	 * Handle the given invocation target exception. Should only be called if no
	 * checked exception is expected to be thrown by the target method.
	 * <p>Throws the underlying RuntimeException or Error in case of such a root
	 * cause. Throws an IllegalStateException else.
	 * @param ex the invocation target exception to handle
	 */
	public static void handleInvocationTargetException(InvocationTargetException ex) {
		rethrowRuntimeException(ex.getTargetException());
	}
	
	public static void rethrowRuntimeException(Throwable ex) {
		if (ex instanceof RuntimeException) {
			throw (RuntimeException) ex;
		}
		if (ex instanceof Error) {
			throw (Error) ex;
		}
		throw new UndeclaredThrowableException(ex);
	}
	
//	public static String[] getMethodParamNames(Method method){
//		final String methodName = method.getName();
//		final Class<?>[] methodParameterTypes = method.getParameterTypes();
//		final int methodParameterCount = methodParameterTypes.length;
//		final String className = method.getDeclaringClass().getName();
//		final boolean isStatic = Modifier.isStatic(method.getModifiers());
//		final String[] methodParametersNames = new String[methodParameterCount];
//
//		try {
//			ClassReader cr = new ClassReader(className);
//			ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
//		} catch (IOException e) {
//			e.printStackTrace();
//		}
//		return null;
//	}
	
	
}
